This helper, vfio_pci_core_mmap_prep_dmabuf(), creates a single-range
DMABUF for the purpose of mapping a PCI BAR. This is used in a future
commit by VFIO's ordinary mmap() path.
This function transfers ownership of the VFIO device fd to the
DMABUF, which fput()s when it's released.
Refactor the existing vfio_pci_core_feature_dma_buf() to split out
export code common to the two paths, VFIO_DEVICE_FEATURE_DMA_BUF and
this new VFIO_BAR mmap().
Signed-off-by: Matt Evans <mattev@meta.com>
---
drivers/vfio/pci/vfio_pci_dmabuf.c | 131 +++++++++++++++++++++--------
drivers/vfio/pci/vfio_pci_priv.h | 4 +
2 files changed, 102 insertions(+), 33 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c
index 63140528dbea..76db340ba592 100644
--- a/drivers/vfio/pci/vfio_pci_dmabuf.c
+++ b/drivers/vfio/pci/vfio_pci_dmabuf.c
@@ -82,6 +82,8 @@ static void vfio_pci_dma_buf_release(struct dma_buf *dmabuf)
up_write(&priv->vdev->memory_lock);
vfio_device_put_registration(&priv->vdev->vdev);
}
+ if (priv->vfile)
+ fput(priv->vfile);
kfree(priv->phys_vec);
kfree(priv);
}
@@ -182,6 +184,41 @@ int vfio_pci_dma_buf_find_pfn(struct vfio_pci_dma_buf *vpdmabuf,
return -EFAULT;
}
+static int vfio_pci_dmabuf_export(struct vfio_pci_core_device *vdev,
+ struct vfio_pci_dma_buf *priv, uint32_t flags,
+ size_t size, bool status_ok)
+{
+ DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+ if (!vfio_device_try_get_registration(&vdev->vdev))
+ return -ENODEV;
+
+ exp_info.ops = &vfio_pci_dmabuf_ops;
+ exp_info.size = size;
+ exp_info.flags = flags;
+ exp_info.priv = priv;
+
+ priv->dmabuf = dma_buf_export(&exp_info);
+ if (IS_ERR(priv->dmabuf)) {
+ vfio_device_put_registration(&vdev->vdev);
+ return PTR_ERR(priv->dmabuf);
+ }
+
+ kref_init(&priv->kref);
+ init_completion(&priv->comp);
+
+ /* dma_buf_put() now frees priv */
+ INIT_LIST_HEAD(&priv->dmabufs_elm);
+ down_write(&vdev->memory_lock);
+ dma_resv_lock(priv->dmabuf->resv, NULL);
+ priv->revoked = !status_ok;
+ list_add_tail(&priv->dmabufs_elm, &vdev->dmabufs);
+ dma_resv_unlock(priv->dmabuf->resv);
+ up_write(&vdev->memory_lock);
+
+ return 0;
+}
+
/*
* This is a temporary "private interconnect" between VFIO DMABUF and iommufd.
* It allows the two co-operating drivers to exchange the physical address of
@@ -300,7 +337,6 @@ int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
{
struct vfio_device_feature_dma_buf get_dma_buf = {};
struct vfio_region_dma_range *dma_ranges;
- DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
struct vfio_pci_dma_buf *priv;
size_t length;
int ret;
@@ -369,46 +405,20 @@ int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
kfree(dma_ranges);
dma_ranges = NULL;
- if (!vfio_device_try_get_registration(&vdev->vdev)) {
- ret = -ENODEV;
+ ret = vfio_pci_dmabuf_export(vdev, priv, get_dma_buf.open_flags,
+ priv->size,
+ __vfio_pci_memory_enabled(vdev));
+ if (ret)
goto err_free_phys;
- }
-
- exp_info.ops = &vfio_pci_dmabuf_ops;
- exp_info.size = priv->size;
- exp_info.flags = get_dma_buf.open_flags;
- exp_info.priv = priv;
-
- priv->dmabuf = dma_buf_export(&exp_info);
- if (IS_ERR(priv->dmabuf)) {
- ret = PTR_ERR(priv->dmabuf);
- goto err_dev_put;
- }
-
- kref_init(&priv->kref);
- init_completion(&priv->comp);
-
- /* dma_buf_put() now frees priv */
- INIT_LIST_HEAD(&priv->dmabufs_elm);
- down_write(&vdev->memory_lock);
- dma_resv_lock(priv->dmabuf->resv, NULL);
- priv->revoked = !__vfio_pci_memory_enabled(vdev);
- list_add_tail(&priv->dmabufs_elm, &vdev->dmabufs);
- dma_resv_unlock(priv->dmabuf->resv);
- up_write(&vdev->memory_lock);
-
/*
* dma_buf_fd() consumes the reference, when the file closes the dmabuf
* will be released.
*/
ret = dma_buf_fd(priv->dmabuf, get_dma_buf.open_flags);
- if (ret < 0)
- goto err_dma_buf;
- return ret;
+ if (ret >= 0)
+ return ret;
-err_dma_buf:
dma_buf_put(priv->dmabuf);
-err_dev_put:
vfio_device_put_registration(&vdev->vdev);
err_free_phys:
kfree(priv->phys_vec);
@@ -419,6 +429,61 @@ int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
return ret;
}
+int vfio_pci_core_mmap_prep_dmabuf(struct vfio_pci_core_device *vdev,
+ struct vm_area_struct *vma,
+ u64 phys_start,
+ u64 pgoff,
+ u64 req_len)
+{
+ struct vfio_pci_dma_buf *priv;
+ const unsigned int nr_ranges = 1;
+ int ret;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->phys_vec = kcalloc(nr_ranges, sizeof(*priv->phys_vec),
+ GFP_KERNEL);
+ if (!priv->phys_vec) {
+ ret = -ENOMEM;
+ goto err_free_priv;
+ }
+
+ priv->vdev = vdev;
+ priv->nr_ranges = nr_ranges;
+ priv->size = req_len;
+ priv->phys_vec[0].paddr = phys_start + (pgoff << PAGE_SHIFT);
+ priv->phys_vec[0].len = req_len;
+
+ /*
+ * Creates a DMABUF, adds it to vdev->dmabufs list for
+ * tracking (meaning cleanup or revocation will zap them), and
+ * registers with vfio_device:
+ */
+ ret = vfio_pci_dmabuf_export(vdev, priv, O_CLOEXEC, priv->size, true);
+ if (ret)
+ goto err_free_phys;
+
+ /*
+ * The VMA gets the DMABUF file so that other users can locate
+ * the DMABUF via a VA. Ownership of the original VFIO device
+ * file being mmap()ed transfers to priv, and is put when the
+ * DMABUF is released.
+ */
+ priv->vfile = vma->vm_file;
+ vma->vm_file = priv->dmabuf->file;
+ vma->vm_private_data = priv;
+
+ return 0;
+
+err_free_phys:
+ kfree(priv->phys_vec);
+err_free_priv:
+ kfree(priv);
+ return ret;
+}
+
void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, bool revoked)
{
struct vfio_pci_dma_buf *priv;
diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h
index 5cc8c85a2153..5fd3a6e00a0e 100644
--- a/drivers/vfio/pci/vfio_pci_priv.h
+++ b/drivers/vfio/pci/vfio_pci_priv.h
@@ -30,6 +30,7 @@ struct vfio_pci_dma_buf {
size_t size;
struct phys_vec *phys_vec;
struct p2pdma_provider *provider;
+ struct file *vfile;
u32 nr_ranges;
struct kref kref;
struct completion comp;
@@ -128,6 +129,9 @@ int vfio_pci_dma_buf_find_pfn(struct vfio_pci_dma_buf *vpdmabuf,
unsigned long address,
unsigned int order,
unsigned long *out_pfn);
+int vfio_pci_core_mmap_prep_dmabuf(struct vfio_pci_core_device *vdev,
+ struct vm_area_struct *vma,
+ u64 phys_start, u64 pgoff, u64 req_len);
#ifdef CONFIG_VFIO_PCI_DMABUF
int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
--
2.47.3On Thu, 12 Mar 2026 11:46:02 -0700
Matt Evans <mattev@meta.com> wrote:
> This helper, vfio_pci_core_mmap_prep_dmabuf(), creates a single-range
> DMABUF for the purpose of mapping a PCI BAR. This is used in a future
> commit by VFIO's ordinary mmap() path.
>
> This function transfers ownership of the VFIO device fd to the
> DMABUF, which fput()s when it's released.
>
> Refactor the existing vfio_pci_core_feature_dma_buf() to split out
> export code common to the two paths, VFIO_DEVICE_FEATURE_DMA_BUF and
> this new VFIO_BAR mmap().
>
> Signed-off-by: Matt Evans <mattev@meta.com>
> ---
> drivers/vfio/pci/vfio_pci_dmabuf.c | 131 +++++++++++++++++++++--------
> drivers/vfio/pci/vfio_pci_priv.h | 4 +
> 2 files changed, 102 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c
> index 63140528dbea..76db340ba592 100644
> --- a/drivers/vfio/pci/vfio_pci_dmabuf.c
> +++ b/drivers/vfio/pci/vfio_pci_dmabuf.c
> @@ -82,6 +82,8 @@ static void vfio_pci_dma_buf_release(struct dma_buf *dmabuf)
> up_write(&priv->vdev->memory_lock);
> vfio_device_put_registration(&priv->vdev->vdev);
> }
> + if (priv->vfile)
> + fput(priv->vfile);
> kfree(priv->phys_vec);
> kfree(priv);
> }
> @@ -182,6 +184,41 @@ int vfio_pci_dma_buf_find_pfn(struct vfio_pci_dma_buf *vpdmabuf,
> return -EFAULT;
> }
>
> +static int vfio_pci_dmabuf_export(struct vfio_pci_core_device *vdev,
> + struct vfio_pci_dma_buf *priv, uint32_t flags,
> + size_t size, bool status_ok)
> +{
> + DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> + if (!vfio_device_try_get_registration(&vdev->vdev))
> + return -ENODEV;
> +
> + exp_info.ops = &vfio_pci_dmabuf_ops;
> + exp_info.size = size;
> + exp_info.flags = flags;
> + exp_info.priv = priv;
> +
> + priv->dmabuf = dma_buf_export(&exp_info);
> + if (IS_ERR(priv->dmabuf)) {
> + vfio_device_put_registration(&vdev->vdev);
> + return PTR_ERR(priv->dmabuf);
> + }
> +
> + kref_init(&priv->kref);
> + init_completion(&priv->comp);
> +
> + /* dma_buf_put() now frees priv */
> + INIT_LIST_HEAD(&priv->dmabufs_elm);
> + down_write(&vdev->memory_lock);
> + dma_resv_lock(priv->dmabuf->resv, NULL);
> + priv->revoked = !status_ok;
Testing __vfio_pci_memory_enabled() outside of memory_lock() is
invalid, so passing it as a parameter outside of the semaphore is
invalid. @status_ok is stale here.
> + list_add_tail(&priv->dmabufs_elm, &vdev->dmabufs);
> + dma_resv_unlock(priv->dmabuf->resv);
> + up_write(&vdev->memory_lock);
> +
> + return 0;
> +}
> +
> /*
> * This is a temporary "private interconnect" between VFIO DMABUF and iommufd.
> * It allows the two co-operating drivers to exchange the physical address of
> @@ -300,7 +337,6 @@ int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
> {
> struct vfio_device_feature_dma_buf get_dma_buf = {};
> struct vfio_region_dma_range *dma_ranges;
> - DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> struct vfio_pci_dma_buf *priv;
> size_t length;
> int ret;
> @@ -369,46 +405,20 @@ int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
> kfree(dma_ranges);
> dma_ranges = NULL;
>
> - if (!vfio_device_try_get_registration(&vdev->vdev)) {
> - ret = -ENODEV;
> + ret = vfio_pci_dmabuf_export(vdev, priv, get_dma_buf.open_flags,
> + priv->size,
> + __vfio_pci_memory_enabled(vdev));
> + if (ret)
> goto err_free_phys;
> - }
> -
> - exp_info.ops = &vfio_pci_dmabuf_ops;
> - exp_info.size = priv->size;
> - exp_info.flags = get_dma_buf.open_flags;
> - exp_info.priv = priv;
> -
> - priv->dmabuf = dma_buf_export(&exp_info);
> - if (IS_ERR(priv->dmabuf)) {
> - ret = PTR_ERR(priv->dmabuf);
> - goto err_dev_put;
> - }
> -
> - kref_init(&priv->kref);
> - init_completion(&priv->comp);
> -
> - /* dma_buf_put() now frees priv */
> - INIT_LIST_HEAD(&priv->dmabufs_elm);
> - down_write(&vdev->memory_lock);
> - dma_resv_lock(priv->dmabuf->resv, NULL);
> - priv->revoked = !__vfio_pci_memory_enabled(vdev);
Tested under memory_lock. It was correct previously.
> - list_add_tail(&priv->dmabufs_elm, &vdev->dmabufs);
> - dma_resv_unlock(priv->dmabuf->resv);
> - up_write(&vdev->memory_lock);
> -
> /*
> * dma_buf_fd() consumes the reference, when the file closes the dmabuf
> * will be released.
> */
> ret = dma_buf_fd(priv->dmabuf, get_dma_buf.open_flags);
> - if (ret < 0)
> - goto err_dma_buf;
> - return ret;
> + if (ret >= 0)
> + return ret;
>
> -err_dma_buf:
> dma_buf_put(priv->dmabuf);
> -err_dev_put:
> vfio_device_put_registration(&vdev->vdev);
> err_free_phys:
> kfree(priv->phys_vec);
> @@ -419,6 +429,61 @@ int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
> return ret;
> }
>
> +int vfio_pci_core_mmap_prep_dmabuf(struct vfio_pci_core_device *vdev,
> + struct vm_area_struct *vma,
> + u64 phys_start,
> + u64 pgoff,
> + u64 req_len)
> +{
> + struct vfio_pci_dma_buf *priv;
> + const unsigned int nr_ranges = 1;
> + int ret;
> +
> + priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->phys_vec = kcalloc(nr_ranges, sizeof(*priv->phys_vec),
> + GFP_KERNEL);
> + if (!priv->phys_vec) {
> + ret = -ENOMEM;
> + goto err_free_priv;
> + }
> +
> + priv->vdev = vdev;
> + priv->nr_ranges = nr_ranges;
> + priv->size = req_len;
> + priv->phys_vec[0].paddr = phys_start + (pgoff << PAGE_SHIFT);
> + priv->phys_vec[0].len = req_len;
> +
> + /*
> + * Creates a DMABUF, adds it to vdev->dmabufs list for
> + * tracking (meaning cleanup or revocation will zap them), and
> + * registers with vfio_device:
> + */
> + ret = vfio_pci_dmabuf_export(vdev, priv, O_CLOEXEC, priv->size, true);
> + if (ret)
> + goto err_free_phys;
> +
> + /*
> + * The VMA gets the DMABUF file so that other users can locate
> + * the DMABUF via a VA. Ownership of the original VFIO device
> + * file being mmap()ed transfers to priv, and is put when the
> + * DMABUF is released.
> + */
> + priv->vfile = vma->vm_file;
> + vma->vm_file = priv->dmabuf->file;
AIUI, this affects what the user sees in /proc/<pid>/maps, right?
Previously a memory range could be clearly associated with a specific
vfio device, now, only for vfio-pci devices, I think the range is
associated to a nondescript dmabuf. If so, is that an acceptable, user
visible, debugging friendly change (ex. lsof)? Thanks,
Alex
> + vma->vm_private_data = priv;
> +
> + return 0;
> +
> +err_free_phys:
> + kfree(priv->phys_vec);
> +err_free_priv:
> + kfree(priv);
> + return ret;
> +}
> +
> void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, bool revoked)
> {
> struct vfio_pci_dma_buf *priv;
> diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h
> index 5cc8c85a2153..5fd3a6e00a0e 100644
> --- a/drivers/vfio/pci/vfio_pci_priv.h
> +++ b/drivers/vfio/pci/vfio_pci_priv.h
> @@ -30,6 +30,7 @@ struct vfio_pci_dma_buf {
> size_t size;
> struct phys_vec *phys_vec;
> struct p2pdma_provider *provider;
> + struct file *vfile;
> u32 nr_ranges;
> struct kref kref;
> struct completion comp;
> @@ -128,6 +129,9 @@ int vfio_pci_dma_buf_find_pfn(struct vfio_pci_dma_buf *vpdmabuf,
> unsigned long address,
> unsigned int order,
> unsigned long *out_pfn);
> +int vfio_pci_core_mmap_prep_dmabuf(struct vfio_pci_core_device *vdev,
> + struct vm_area_struct *vma,
> + u64 phys_start, u64 pgoff, u64 req_len);
>
> #ifdef CONFIG_VFIO_PCI_DMABUF
> int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
Hi Alex,
On Wed, Mar 18, 2026 at 8:04 PM Alex Williamson <alex@shazbot.org> wrote:
> On Thu, 12 Mar 2026 11:46:02 -0700
> Matt Evans <mattev@meta.com> wrote:
>
> > This helper, vfio_pci_core_mmap_prep_dmabuf(), creates a single-range
> > DMABUF for the purpose of mapping a PCI BAR. This is used in a future
> > commit by VFIO's ordinary mmap() path.
> >
> > This function transfers ownership of the VFIO device fd to the
> > DMABUF, which fput()s when it's released.
> >
> > Refactor the existing vfio_pci_core_feature_dma_buf() to split out
> > export code common to the two paths, VFIO_DEVICE_FEATURE_DMA_BUF and
> > this new VFIO_BAR mmap().
> >
> > Signed-off-by: Matt Evans <mattev@meta.com>
> > ---
> > drivers/vfio/pci/vfio_pci_dmabuf.c | 131 +++++++++++++++++++++--------
> > drivers/vfio/pci/vfio_pci_priv.h | 4 +
> > 2 files changed, 102 insertions(+), 33 deletions(-)
> >
> > diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c
> > index 63140528dbea..76db340ba592 100644
> > --- a/drivers/vfio/pci/vfio_pci_dmabuf.c
> > +++ b/drivers/vfio/pci/vfio_pci_dmabuf.c
> > @@ -82,6 +82,8 @@ static void vfio_pci_dma_buf_release(struct dma_buf *dmabuf)
> > up_write(&priv->vdev->memory_lock);
> > vfio_device_put_registration(&priv->vdev->vdev);
> > }
> > + if (priv->vfile)
> > + fput(priv->vfile);
> > kfree(priv->phys_vec);
> > kfree(priv);
> > }
> > @@ -182,6 +184,41 @@ int vfio_pci_dma_buf_find_pfn(struct vfio_pci_dma_buf *vpdmabuf,
> > return -EFAULT;
> > }
> >
> > +static int vfio_pci_dmabuf_export(struct vfio_pci_core_device *vdev,
> > + struct vfio_pci_dma_buf *priv, uint32_t flags,
> > + size_t size, bool status_ok)
> > +{
> > + DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> > +
> > + if (!vfio_device_try_get_registration(&vdev->vdev))
> > + return -ENODEV;
> > +
> > + exp_info.ops = &vfio_pci_dmabuf_ops;
> > + exp_info.size = size;
> > + exp_info.flags = flags;
> > + exp_info.priv = priv;
> > +
> > + priv->dmabuf = dma_buf_export(&exp_info);
> > + if (IS_ERR(priv->dmabuf)) {
> > + vfio_device_put_registration(&vdev->vdev);
> > + return PTR_ERR(priv->dmabuf);
> > + }
> > +
> > + kref_init(&priv->kref);
> > + init_completion(&priv->comp);
> > +
> > + /* dma_buf_put() now frees priv */
> > + INIT_LIST_HEAD(&priv->dmabufs_elm);
> > + down_write(&vdev->memory_lock);
> > + dma_resv_lock(priv->dmabuf->resv, NULL);
> > + priv->revoked = !status_ok;
>
> Testing __vfio_pci_memory_enabled() outside of memory_lock() is
> invalid, so passing it as a parameter outside of the semaphore is
> invalid. @status_ok is stale here.
So it is, arrrrrgh. Thank you for that; I've found a couple of other
choice bugs in that RFC, and will resolve all of this in a repost
soon.
[snip]
> > +
> > + /*
> > + * The VMA gets the DMABUF file so that other users can locate
> > + * the DMABUF via a VA. Ownership of the original VFIO device
> > + * file being mmap()ed transfers to priv, and is put when the
> > + * DMABUF is released.
> > + */
> > + priv->vfile = vma->vm_file;
> > + vma->vm_file = priv->dmabuf->file;
>
> AIUI, this affects what the user sees in /proc/<pid>/maps, right?
> Previously a memory range could be clearly associated with a specific
> vfio device, now, only for vfio-pci devices, I think the range is
> associated to a nondescript dmabuf. If so, is that an acceptable, user
> visible, debugging friendly change (ex. lsof)? Thanks,
(Jason, your comment noted with thanks, replying to you both here to
save electrons.)
Great question; a formatting change there is inherent to moving to a
DMABUF (which generates a "/dmabuf:" prefix to a user-defined name).
If we can accept that it changes at all, then I agree this then should
output nice debug: at least the cdev name and resource index, and
we've the opportunity to include the BDF too. I've added this; an
example line of /proc/<pid>/maps:
ffffb8070000-ffffbc040000 rw-s 00030000 00:0b 5
/dmabuf:vfio0:0000:00:03.0/1
Note the file offset used to include the resource index up at
VFIO_PCI_OFFSET_SHIFT but this DMABUF version doesn't do that, so I'm
proposing appending a "/%u" for the index. Above is a map of BAR1,
offset 0x30000. If people feel strongly about the existing aesthetic
then we could keep the index encoded in vm_pgoff to retain the same
offset field in /proc/<pid>/maps, but it'd be less neat masking it
back out in a few places.
The default name of a DMABUF acquired through
VFIO_DEVICE_FEATURE_DMA_BUF would still be "/dmabuf:" and I think it
should stay this way since a better name should be supplied by
userspace. The default at least differentiates them from VFIO device
fd mappings.
Many thanks,
Matt
>
> Alex
>
> > + vma->vm_private_data = priv;
> > +
> > + return 0;
> > +
> > +err_free_phys:
> > + kfree(priv->phys_vec);
> > +err_free_priv:
> > + kfree(priv);
> > + return ret;
> > +}
> > +
> > void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, bool revoked)
> > {
> > struct vfio_pci_dma_buf *priv;
> > diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h
> > index 5cc8c85a2153..5fd3a6e00a0e 100644
> > --- a/drivers/vfio/pci/vfio_pci_priv.h
> > +++ b/drivers/vfio/pci/vfio_pci_priv.h
> > @@ -30,6 +30,7 @@ struct vfio_pci_dma_buf {
> > size_t size;
> > struct phys_vec *phys_vec;
> > struct p2pdma_provider *provider;
> > + struct file *vfile;
> > u32 nr_ranges;
> > struct kref kref;
> > struct completion comp;
> > @@ -128,6 +129,9 @@ int vfio_pci_dma_buf_find_pfn(struct vfio_pci_dma_buf *vpdmabuf,
> > unsigned long address,
> > unsigned int order,
> > unsigned long *out_pfn);
> > +int vfio_pci_core_mmap_prep_dmabuf(struct vfio_pci_core_device *vdev,
> > + struct vm_area_struct *vma,
> > + u64 phys_start, u64 pgoff, u64 req_len);
> >
> > #ifdef CONFIG_VFIO_PCI_DMABUF
> > int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
>
On Wed, Mar 18, 2026 at 02:04:08PM -0600, Alex Williamson wrote: > AIUI, this affects what the user sees in /proc/<pid>/maps, right? > Previously a memory range could be clearly associated with a specific > vfio device, now, only for vfio-pci devices, I think the range is > associated to a nondescript dmabuf. Probably > If so, is that an acceptable, user > visible, debugging friendly change (ex. lsof)? Thanks, IIRC there is a way to attach a string to the inode that lsof can display, if we do that right it should be good enough. Jason
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